General Electric Company

Fathy F Yassa

Richard I Hartley

Peter F Corbett

Aiman A Abdel-Malek

Sharbel E Noujaim

John J Bloomer

Ertugrul Berkcan

Jerome Johnson Tiemann

Kenneth B Welles, Ii

Steven L Garverick

Chung-Yih Ho

Chukka Srinivas

A fluoroscopic imager for observing a living creature with reduced x-ray dosage uses a video monitor for displaying frames of image samples received during respective ones of frame scan intervals that regularly and successively occur at a display frame rate sufficiently high that brightness flicker is acceptably low to a human observer; an x-ray source that can be gated on for intervals not as long as a display frame; and a fluoroscopic camera, including a raster-scanning video camera and x-ray-to-light conversion apparatus with persistence not appreciably longer than a display frame and frame-filling apparatus. Especially during purely diagnostic procedures, the frame-filling apparatus generates a continuous succession of frames of image samples at the display frame rate by interpolating between successively grabbed frames of image samples. During procedures in which interpolating between successively grabbed frames of image samples introduces unacceptable delay in the observed image, the frame-filling apparatus generates the continuous succession of frames of image samples by extrapolating from each most recently grabbed frame.

Fluoroscopic imager with frame-filling apparatus

A method for fluoroscopically observing a living creature with reduced x-ray dosage is usable with a video monitor for displaying frames of image samples received during respective ones of frame scan intervals that regularly and successively occur at a display frame rate sufficiently high that brightness flicker is acceptably low to a human observer; an x-ray source that can be gated on for intervals not as long as a display frame; a fluoroscopic camera, including a raster-scanning video camera and a x-ray-to-light conversion apparatus with persistence not appreciably longer than a display frame; and frame filling apparatus for grabbing frames of image samples and interpolating between successively grabbed frames of image samples, when necessary, to generate frames of image samples at said display frame rate. During ones of said successive frame scan intervals, x-ray radiation is directed from the gated x-ray source through the living creature; the x-ray shadow of at least a portion of the living creature is viewed with the fluoroscopic camera; and the frame filling apparatus grabs frames of image samples from the raster-scanning video camera to be stored in frame stores and used as bases from which to compute fill frames of image samples. The frame filling apparatus continuously supplies to the video monitor the frames of image samples it generates at display frame rate.

Fluoroscopic method with reduced x-ray dosage

Apparatus for sensing linear displacement of an object between first and second locations along an axis is used to sense conditions that can be made to vary displacement of an object in accordance with the condition, such as temperature, pressure and rotary motion. A light beam projected along an incident light path to the object is reflected along a reflective light path by a reflector affixed to the object. A photo-sensor array in the reflective light path intercepts the reflected light beam and produces samples of the intensity of the reflected image at multiple positions along a line across the array. An imager coupled to the array converts the light samples to representative electrical samples. The resultant light intensity information is provided to an electronic processor which determines a first centroid of the reflected image when the object is at a first location and a second centroid when the object is at a second location, and employs the difference between the first and second centroids to determine the displacement of the object.

Optical sensing apparatus for detecting linear displacement of an object

An oversampled interpolative delta sigma analog-to-digital converter including a delta sigma modulator is provided with a cascade of bit-slice elements at the output of the modulator to form a filter/decimator. Each bit-slice element includes a filter circuit that filters the bit-rate signal in accordance with an arbitrary filter impulse response input signal to provide the converter with a filter characteristic that can be controllably varied without modifying the filter hardware. In each bit-slice element, an adder circuit and a delay circuit decimate the bit-rate signal produced by the delta sigma modulator to provide a digital output signal at a clock cycle rate equal to the Nyquist rate. The filter/decimator also provides encoding of the delta sigma output in 2's complement format.

Digital filter for filtering and decimating delta sigma modulator output

Conversion apparatus is used to convert digital data words to a digit-serial data format wherein digit bit-width is optimal for subsequent processing of the digital data words. Optimization is with regard to throughput efficiency, a measure of integrated circuit performance proportional to throughput rate of integrated circuitry and inversely proportional to the area of that integrated circuitry, comprising processing circuitry and attendant conversion circuitry.

Data format converters for use with digit-serial signals

Apparatus for measuring or compensating for phase or time delay between a reference signal and a desired signal produces an approximate error signal by differentially summing the desired and reference signals. The appoximate error signal is then used, in a feedback loop, to control application of an adaptive delay to each of the reference and desired signals. The total lead or lag difference is represented by the difference between the two delays applied to the reference and desired signals, respectively. The phase or time delay measurement or compensation arrangements may be applied to linear variable differential transformers, synchronous AM detectors, zero crossing detectors and phase locked loops. Variations on this basic technique can yield substantially exact measurement or compensation. The invention is applicable to sampling arrangements including oversampling/decimation or interpolation/decimation to increase compensation accuracy to any desired degree.

Adaptive estimation of phase or delay for both leading and lagging phase

One type of transversal filter using digit-serial signals in its operation comprises a to-digit-serial converter for converting a succession of input data words received at its input port each to a respective succession of m-bit-wide digits supplied from its output port in order of progressively greater significance, m being a positive plural integer; a clocked delay line having an input tap connected for responding to the m-bit-wide digits supplied from the output port of the to-digit-serial converter and having at least one further tap for supplying a respective tap signal; and means for performing a weighted summation of the input signal to the clocked delay line and each tap signal from the clocked delay line, to generate a filter response in digit-serial format. Another type of transversal filter, which uses digit-serial signals in its operation, comprises a plurality, p in number, of parallel-to-digit-serial converters, each for generating a respective m-bit-wide digit-serial data stream by converting n-parallel-bit words in an input signal to the digital filter, m being a positive integer and n being the product of m and p; a plurality of tapped delay lines having respective input taps connected from respective ones of said parallel-to-digit-serial converters and each having at least one further tap; means for generating p different phases of filter response in digit-serial form by weighting and summing digital signals taken from respective taps on ones of the p tapped delay lines; and p digit-serial-to-parallel converters for converting, on a cyclic basis, the different phases of filter response to parallel-bit words in an output signal from the digital filter.

Digit-serial transversal filters

Increased performance of digital integrated circuits by processing with

To-digit-serial converters for systems processing data in digit-serial

Sine and cosine waves are simultaneously accumulated in accordance with the following equations in apparatus embodying the invention.

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Clifton Park, NY, United States of America

Fathy F Yassa